Systems and methods for algae cultivation using direct air capture

Abstract

Embodiments of the disclosure provide systems and methods for supplying an algae cultivation fluid with nutrients (e.g., carbon dioxide and nitrogen) directly from the atmosphere. Supplying nutrients directly from the atmosphere reduces operational costs and environmental impacts, as well as provides greater flexibility in locating algae farms.

We claim: 
     
         1 . A method comprising the steps of:
 culturing algae in at least one channel having a bottom surface, opposing side walls coupled to the bottom surface, and an algae cultivation fluid disposed in the at least one channel; and   applying bore waves through the algae cultivation fluid at a bore wave frequency sufficient to disrupt an air-liquid interface of the algae cultivation fluid to induce direct absorption of atmospheric nitrogen from air into the algae cultivation fluid; and   wherein a majority of the nitrogen in the algae is from atmospheric nitrogen.   
     
     
         2 . The method of  claim 1 , wherein the bottom surface of the channel is sloped. 
     
     
         3 . The method of  claim 2 , wherein the slope of the bottom surface is less than 0.5%. 
     
     
         4 . The method of  claim 1  further including passing the bore waves through one or more air-liquid mixing devices configured within the at least one channel. 
     
     
         5 . The method of  claim 4 , wherein the at least one channel includes from one air-liquid mixing device for every 300 ft 2  of surface of the at least one channel to one air-liquid mixing device for every 400,000 ft 2  of surface of the at least one channel. 
     
     
         6 . The method of  claim 4 , wherein one or more of the air-liquid mixing devices are powered by a flow of the bore waves. 
     
     
         7 . The method of  claim 4 , wherein a rate of air-liquid mixing is adjusted during the cultivation to reduce energy consumption. 
     
     
         8 . The method of  claim 7 , wherein solar energy is used to power the one or more air-liquid mixing devices, and wherein a rate of air-liquid mixing is greater during times of higher solar radiation relative to times of lower solar radiation. 
     
     
         9 . The method of  claim 4 , wherein the one or more air-liquid mixing devices generate air bubbles in the algae cultivation fluid. 
     
     
         10 . The method of  claim 9 , wherein a bubble generation rate is increased when the bore wave passes one of the air-liquid mixing devices, and is decreased during a period in between the bore waves. 
     
     
         11 . The method of  claim 1 , wherein the at least one channel has a surface area of at least 100 ft 2 . 
     
     
         12 . The method of  claim 1 , wherein the at least one channel has a surface area from 10,000 ft 2  to 20,000,000 ft 2 . 
     
     
         13 . The method of  claim 1 , wherein the bore wave frequency is adjusted by displacing a gate in a bore wave generator. 
     
     
         14 . The method of  claim 13  further including displacing the gate at a frequency from 10 seconds to 300 seconds to apply the bore waves through the algae cultivation fluid. 
     
     
         15 . The method of  claim 1 , wherein a bore wave intensity is adjusted by a height of the algae cultivation fluid behind a gate in a bore wave generator. 
     
     
         16 . The method of  claim 15 , wherein the height of algae cultivation fluid is adjusted by a rate of filling of an area behind the gate with algae cultivation fluid. 
     
     
         17 . The method of  claim 1  further including measuring at least one process parameter; and adjusting the bore wave frequency, a bore wave intensity, or a combination thereof based on the at least one process parameter or rate of change of the at least one process parameter. 
     
     
         18 . The method of  claim 17 , wherein the at least one process parameter is selected from the group consisting of a pH, a dissolved oxygen content, a bicarbonate concentration, a nitrogen concentration, solar intensity, algae growth rate, turbidity, optical density, and temperature. 
     
     
         19 . The method of  claim 17 , further including adjusting the bore wave frequency, intensity, or a combination thereof to maintain a desired set-point of the at least one process parameter.